By analyzing the phenomenon that solid carbon dioxide and gaseous carbon dioxide react with the same amount of lime water, students can understand the composition, structure, properties and changes of substances at the molecular level. Be able to analyze and solve practical problems from the perspective of combining macro and micro.

2. Change ideas and balance ideas

By exploring the reaction between solid carbon dioxide and limewater, students should pay attention not only to the changes of substances, but also to the changes of pressure and energy when observing experimental phenomena, so that they can analyze chemical reactions dynamically from multiple angles and solve practical problems by using chemical reaction principles.

3. Evidence reasoning and model cognition

The description of learning objectives cultivates students' evidence consciousness by looking for evidence, and establishes the logical relationship among viewpoints, conclusions and evidence: let students know that they can understand the research through analysis and reasoning.

Modeling the essential characteristics, constituent elements and their relationships of objects. Be able to use models to explain chemical phenomena and explain the nature and laws of phenomena.

4. Experimental inquiry and innovative consciousness

By exploring the reaction between solid carbon dioxide and clarified limewater, students can realize that scientific inquiry is a scientific practice activity of scientific explanation, discovery, creation and application. Cultivate students' innovative thinking in scientific inquiry, so as to promote the efficiency of junior middle school students' chemistry learning.

5. Scientific spirit and social responsibility

Through the study of this lesson, cultivate students' rigorous and realistic scientific attitude and explore the awareness of the unknown and truth. In the experiment, cultivate students' scientific spirit of unity and cooperation and dare to question.